Iranian history—considering its religious structure—has always been linked to a concept called “Fatwa”. Fatwa has been formed as a result of many factors and as a multifunctional issue, and it has been used as an important factor in political discussions and decisions. Fatwa, as a moving social parameter, has created great results in Iranian history. In this regard, the history of Iran in the Saljuqid era, considering the political-social situations, has witnessed many Fatwas in reaching its particular aims. This paper, using an analytic approach while analyzing the issued Fatwas in Iran in this era, claims that Fatwas—in their political function—have been used for removing the opposition groups, as a political removal of other opponents, justification of political-religious actions and also for tribal-religious purposes. On the other side, the Saljuqid’s political control over religion in general and Muftis in particular, will be understandable in this perspective. Among the findings of the present study are patterns of this issue, which are in line with scientific theorization in Iranian history.